diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index 2c3435d55d01..305d6dd6bdef 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -15,6 +15,7 @@
 #include <linux/seq_file.h>
 #include <linux/debugfs.h>
 #include <linux/pm_wakeirq.h>
+#include <linux/types.h>
 #include <trace/events/power.h>
 
 #include "power.h"
@@ -806,16 +807,31 @@ EXPORT_SYMBOL_GPL(pm_wakeup_event);
 
 void pm_get_active_wakeup_sources(char *pending_wakeup_source, size_t max)
 {
-	struct wakeup_source *ws;
+	struct wakeup_source *ws, *last_active_ws = NULL;
 	int len = 0;
+	bool active = false;
+
 	rcu_read_lock();
-	len += snprintf(pending_wakeup_source, max, "Pending Wakeup Sources: ");
 	list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
 		if (ws->active) {
-			len += snprintf(pending_wakeup_source + len, max,
+			if (!active)
+				len += scnprintf(pending_wakeup_source, max,
+						"Pending Wakeup Sources: ");
+			len += scnprintf(pending_wakeup_source + len, max - len,
 				"%s ", ws->name);
+			active = true;
+		} else if (!active &&
+			   (!last_active_ws ||
+			    ktime_to_ns(ws->last_time) >
+			    ktime_to_ns(last_active_ws->last_time))) {
+			last_active_ws = ws;
 		}
 	}
+	if (!active && last_active_ws) {
+		scnprintf(pending_wakeup_source, max,
+				"Last active Wakeup Source: %s",
+				last_active_ws->name);
+	}
 	rcu_read_unlock();
 }
 EXPORT_SYMBOL_GPL(pm_get_active_wakeup_sources);